Message delivery systems that deliver messages whose contents are related to geographic points of interest are highly valued by travelers. Generally, as a traveler moves past a point of interest covered by such a message delivery system, the system delivers, performs, displays, announces, or otherwise conveys a message to the traveler. Desirably, this message imparts information that describes or otherwise relates to the point of interest being passed.
In a primitive form of such a message delivery system, travelers view a sign that informs them to tune their radios to a particular channel or frequency where they may receive a recorded message. Typically, the range of the station delivering the message is either undesirably large or undesirably small. When the range is too large, precise matching of message delivery to the geographic point of interest is difficult. The message may be received even when the traveler is nowhere near the point of interest. Messages are typically repeated one or more times as the traveler moves through the range of reception. The repetition of messages is particularly annoying to a traveler because a traveler in an unfamiliar area may otherwise be nearly overwhelmed with new information. In addition, only a limited number of messages may be delivered for a given geographic area.
When the range is too small, radio reception is typically poor even when the traveler is precisely at the point of interest. When the traveler moves through this small range, an entire message may not get delivered while the traveler's radio is within range.
In either case, a message is often delivered starting somewhere in the middle of the message rather than at a beginning of a message. In a typical scenario, the traveler first experiences a message from middle to end, then waits for the message to repeat. If the delivery range is sufficiently large and if the traveler waits long enough, he or she then experiences the message from beginning to middle, at which point the message repeats for the traveler. Starting message delivery in the middle is undesirable because it is more difficult for a traveler to understand the ending parts of a message when the beginning parts have not yet been delivered.
Attempts have been made to improve upon such primitive systems. However, such attempts typically cause other serious problems. For example, systems have been designed to broadcast message index codes which are evaluated by special purpose receivers. Each receiver has a repertoire of stored messages, and each receiver delivers the message from the repertoire that corresponds to the received index. This message may be delivered from beginning to end. However, this special purpose receiver is inflexible for message changes and is difficult to customize for areas having a dense distribution of points of interest. Typically, drivers of vehicles equipped with such special purpose radios must be extensively involved in tuning radios and in insuring that the radios remain programmed with a current repertoire of messages.
Moreover, conventional message delivery systems fail to provide an implementation that is well suited for public transportation. Systems that require vehicle drivers to tune a radio to specific stations are not suited for public transportation. Driver cooperation is an essential element of successful message delivery, and the drivers are typically uninterested in receiving the messages.
In addition, travelers in public transportation, such as tourists who may have arrived in a particular city by aircraft, may be disoriented as to north, south, east, and west absolute directions. Conventional message delivery systems do not impart relative directional information, such as right and left, to such disoriented travelers. Thus, conventional message delivery systems do not adequately provide a message content that distinguishes geographic points of interest on one side of a road from those on another.